The invention relates generally to the field of oral care, and in particular to toothbrushes. More specifically, the invention relates to a brush head for a toothbrush.
U.S. Pat. No. 5,577,285 (the ""285 patent) discloses an electric toothbrush with a rotary bristle supporting structure. In one embodiment of the invention shown in FIG. 6, the brush head is driven such that an outer ring of bristles 45a and an inner ring of bristles 45b are moved in an alternating rotary motion in opposite directions. While such an arrangement is beneficial for cleaning, for example, the bucal or lingual tooth surfaces, the lack of motion of any of the bristles in an up and down pattern results in a less than optimal cleaning of the inter-dental tooth surfaces.
FIG. 9 of the ""285 patent discloses an additional embodiment of the invention in, which all of the bristles 45 are rotated about an axis 54 while also being moved in an up and down motion parallel to this axis. This embodiment will provide enhanced cleaning of the inter-dental tooth surfaces. However, the fact that all of the bristles are moved up and down limits the depth of penetration that the bristles can obtain between the teeth. This is because while some of the bristles are trying to penetrate between the teeth, others are pressing against, for example, the bucal tooth surface, thus limiting the motion of the brush head towards the teeth.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a head for a toothbrush includes a neck and, first and second sets of one or more bristles each. The first and second sets are indirectly supported by the neck and movable relative to each other such that at least one component of this relative movement causes the bristle(s) of the first set to be raised and/or lowered relative to the bristle(s) in the second set. The first and second sets of bristles both are movable relative to the neck.
By providing such raising and/or lowering relative movement between two sets of bristles, one set of bristles can penetrate between the teeth without hindrance from the other set of bristles, thereby enhancing cleaning of the inter-dental tooth surfaces.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.